SF: Avoid registering DisplayDevice with Scheduler

The Scheduler should only care about the RefreshRateSelector part, and
should not needlessly extend the compositionengine::Display's lifetime
until the DisplayDevice is unregistered.

Make Scheduler::registerDisplay infallible, such that SurfaceFlinger::
processDisplayChanged does not need to unregister before registering.

Bug: 241285191
Test: libsurfaceflinger_unittest
Change-Id: I12b3855167e98f48ae368d39264edcb456efb293
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 499cee6..0e1b775 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -94,7 +94,7 @@
     }
 }
 
-void Scheduler::setRefreshRateSelector(std::shared_ptr<RefreshRateSelector> selectorPtr) {
+void Scheduler::setRefreshRateSelector(RefreshRateSelectorPtr selectorPtr) {
     // The current RefreshRateSelector instance may outlive this call, so unbind its idle timer.
     {
         // mRefreshRateSelectorLock is not locked here to avoid the deadlock
@@ -126,13 +126,12 @@
     mRefreshRateSelector->startIdleTimer();
 }
 
-void Scheduler::registerDisplay(sp<const DisplayDevice> display) {
-    if (display->isPrimary()) {
-        mLeaderDisplayId = display->getPhysicalId();
+void Scheduler::registerDisplay(PhysicalDisplayId displayId, RefreshRateSelectorPtr selectorPtr) {
+    if (!mLeaderDisplayId) {
+        mLeaderDisplayId = displayId;
     }
 
-    const bool ok = mDisplays.try_emplace(display->getPhysicalId(), std::move(display)).second;
-    ALOGE_IF(!ok, "%s: Duplicate display", __func__);
+    mRefreshRateSelectors.emplace_or_replace(displayId, std::move(selectorPtr));
 }
 
 void Scheduler::unregisterDisplay(PhysicalDisplayId displayId) {
@@ -140,7 +139,7 @@
         mLeaderDisplayId.reset();
     }
 
-    mDisplays.erase(displayId);
+    mRefreshRateSelectors.erase(displayId);
 }
 
 void Scheduler::run() {
@@ -711,10 +710,9 @@
 
     const auto globalSignals = makeGlobalSignals();
 
-    for (const auto& [id, display] : mDisplays) {
+    for (const auto& [id, selectorPtr] : mRefreshRateSelectors) {
         auto rankedRefreshRates =
-                display->holdRefreshRateSelector()
-                        ->getRankedRefreshRates(mPolicy.contentRequirements, globalSignals);
+                selectorPtr->getRankedRefreshRates(mPolicy.contentRequirements, globalSignals);
 
         for (const auto& [modePtr, score] : rankedRefreshRates.ranking) {
             const auto [it, inserted] = refreshRateTallies.try_emplace(modePtr->getFps(), score);
@@ -733,7 +731,7 @@
 
     // Find the first refresh rate common to all displays.
     while (maxScoreIt != refreshRateTallies.cend() &&
-           maxScoreIt->second.displayCount != mDisplays.size()) {
+           maxScoreIt->second.displayCount != mRefreshRateSelectors.size()) {
         ++maxScoreIt;
     }
 
@@ -742,7 +740,8 @@
         for (auto it = maxScoreIt + 1; it != refreshRateTallies.cend(); ++it) {
             const auto [fps, tally] = *it;
 
-            if (tally.displayCount == mDisplays.size() && tally.score > maxScoreIt->second.score) {
+            if (tally.displayCount == mRefreshRateSelectors.size() &&
+                tally.score > maxScoreIt->second.score) {
                 maxScoreIt = it;
             }
         }
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 39c41b9..901cf74 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -39,7 +39,6 @@
 
 #include "Display/DisplayMap.h"
 #include "Display/DisplayModeRequest.h"
-#include "DisplayDevice.h"
 #include "EventThread.h"
 #include "FrameRateOverrideMappings.h"
 #include "LayerHistory.h"
@@ -107,10 +106,11 @@
     virtual ~Scheduler();
 
     void startTimers();
-    void setRefreshRateSelector(std::shared_ptr<RefreshRateSelector>)
-            EXCLUDES(mRefreshRateSelectorLock);
 
-    void registerDisplay(sp<const DisplayDevice>);
+    using RefreshRateSelectorPtr = std::shared_ptr<RefreshRateSelector>;
+    void setRefreshRateSelector(RefreshRateSelectorPtr) EXCLUDES(mRefreshRateSelectorLock);
+
+    void registerDisplay(PhysicalDisplayId, RefreshRateSelectorPtr);
     void unregisterDisplay(PhysicalDisplayId);
 
     void run();
@@ -299,8 +299,7 @@
             EXCLUDES(mRefreshRateSelectorLock);
     android::impl::EventThread::GetVsyncPeriodFunction makeGetVsyncPeriodFunction() const;
 
-    std::shared_ptr<RefreshRateSelector> holdRefreshRateSelector() const
-            EXCLUDES(mRefreshRateSelectorLock) {
+    RefreshRateSelectorPtr holdRefreshRateSelector() const EXCLUDES(mRefreshRateSelectorLock) {
         std::scoped_lock lock(mRefreshRateSelectorLock);
         return mRefreshRateSelector;
     }
@@ -336,7 +335,7 @@
 
     mutable std::mutex mPolicyLock;
 
-    display::PhysicalDisplayMap<PhysicalDisplayId, sp<const DisplayDevice>> mDisplays;
+    display::PhysicalDisplayMap<PhysicalDisplayId, RefreshRateSelectorPtr> mRefreshRateSelectors;
     std::optional<PhysicalDisplayId> mLeaderDisplayId;
 
     struct Policy {
@@ -359,8 +358,9 @@
         std::optional<ModeChangedParams> cachedModeChangedParams;
     } mPolicy GUARDED_BY(mPolicyLock);
 
+    // TODO(b/255635821): Remove this by instead looking up the `mLeaderDisplayId` selector.
     mutable std::mutex mRefreshRateSelectorLock;
-    std::shared_ptr<RefreshRateSelector> mRefreshRateSelector GUARDED_BY(mRefreshRateSelectorLock);
+    RefreshRateSelectorPtr mRefreshRateSelector GUARDED_BY(mRefreshRateSelectorLock);
 
     std::mutex mVsyncTimelineLock;
     std::optional<hal::VsyncPeriodChangeTimeline> mLastVsyncPeriodChangeTimeline
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 89d905a..aa930bc 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2937,11 +2937,15 @@
                                                  displaySurface, producer);
 
     if (mScheduler && !display->isVirtual()) {
+        auto selectorPtr = display->holdRefreshRateSelector();
+
         // Display modes are reloaded on hotplug reconnect.
         if (display->isPrimary()) {
-            mScheduler->setRefreshRateSelector(display->holdRefreshRateSelector());
+            mScheduler->setRefreshRateSelector(selectorPtr);
         }
-        mScheduler->registerDisplay(display);
+
+        const auto displayId = display->getPhysicalId();
+        mScheduler->registerDisplay(displayId, std::move(selectorPtr));
         dispatchDisplayHotplugEvent(display->getPhysicalId(), true);
     }
 
@@ -2994,8 +2998,6 @@
             display->disconnect();
             if (display->isVirtual()) {
                 releaseVirtualDisplay(display->getVirtualId());
-            } else {
-                mScheduler->unregisterDisplay(display->getPhysicalId());
             }
         }
 
@@ -3409,8 +3411,8 @@
         }
 
         mScheduler->createVsyncSchedule(features);
-        mScheduler->setRefreshRateSelector(std::move(selectorPtr));
-        mScheduler->registerDisplay(display);
+        mScheduler->setRefreshRateSelector(selectorPtr);
+        mScheduler->registerDisplay(display->getPhysicalId(), std::move(selectorPtr));
     }
     setVsyncEnabled(false);
     mScheduler->startTimers();
diff --git a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
index 066083f..ea4666e 100644
--- a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
@@ -20,7 +20,6 @@
 
 #include <mutex>
 
-#include "FakeDisplayInjector.h"
 #include "Scheduler/EventThread.h"
 #include "Scheduler/RefreshRateSelector.h"
 #include "TestableScheduler.h"
@@ -41,7 +40,6 @@
 
 using MockEventThread = android::mock::EventThread;
 using MockLayer = android::mock::MockLayer;
-using FakeDisplayDeviceInjector = TestableSurfaceFlinger::FakeDisplayDeviceInjector;
 
 class SchedulerTest : public testing::Test {
 protected:
@@ -90,10 +88,6 @@
     sp<MockEventThreadConnection> mEventThreadConnection;
 
     TestableSurfaceFlinger mFlinger;
-    Hwc2::mock::PowerAdvisor mPowerAdvisor;
-    sp<android::mock::NativeWindow> mNativeWindow = sp<android::mock::NativeWindow>::make();
-
-    FakeDisplayInjector mFakeDisplayInjector{mFlinger, mPowerAdvisor, mNativeWindow};
 };
 
 SchedulerTest::SchedulerTest() {
@@ -240,14 +234,11 @@
 }
 
 TEST_F(SchedulerTest, chooseRefreshRateForContentSelectsMaxRefreshRate) {
-    const auto display = mFakeDisplayInjector.injectInternalDisplay(
-            [&](FakeDisplayDeviceInjector& injector) {
-                injector.setDisplayModes(kDisplay1Modes, kDisplay1Mode60->getId());
-            },
-            {.displayId = kDisplayId1});
+    const auto selectorPtr =
+            std::make_shared<RefreshRateSelector>(kDisplay1Modes, kDisplay1Mode60->getId());
 
-    mScheduler->registerDisplay(display);
-    mScheduler->setRefreshRateSelector(display->holdRefreshRateSelector());
+    mScheduler->registerDisplay(kDisplayId1, selectorPtr);
+    mScheduler->setRefreshRateSelector(selectorPtr);
 
     const sp<MockLayer> layer = sp<MockLayer>::make(mFlinger.flinger());
     EXPECT_CALL(*layer, isVisible()).WillOnce(Return(true));
@@ -269,13 +260,9 @@
 }
 
 TEST_F(SchedulerTest, chooseDisplayModesSingleDisplay) {
-    const auto display = mFakeDisplayInjector.injectInternalDisplay(
-            [&](FakeDisplayDeviceInjector& injector) {
-                injector.setDisplayModes(kDisplay1Modes, kDisplay1Mode60->getId());
-            },
-            {.displayId = kDisplayId1});
-
-    mScheduler->registerDisplay(display);
+    mScheduler->registerDisplay(kDisplayId1,
+                                std::make_shared<RefreshRateSelector>(kDisplay1Modes,
+                                                                      kDisplay1Mode60->getId()));
 
     std::vector<RefreshRateSelector::LayerRequirement> layers =
             std::vector<RefreshRateSelector::LayerRequirement>({{.weight = 1.f}, {.weight = 1.f}});
@@ -314,23 +301,16 @@
     EXPECT_EQ(choice->get(), DisplayModeChoice(kDisplay1Mode120, globalSignals));
 
     mScheduler->unregisterDisplay(kDisplayId1);
-    EXPECT_TRUE(mScheduler->mutableDisplays().empty());
+    EXPECT_FALSE(mScheduler->hasRefreshRateSelectors());
 }
 
 TEST_F(SchedulerTest, chooseDisplayModesMultipleDisplays) {
-    const auto display1 = mFakeDisplayInjector.injectInternalDisplay(
-            [&](FakeDisplayDeviceInjector& injector) {
-                injector.setDisplayModes(kDisplay1Modes, kDisplay1Mode60->getId());
-            },
-            {.displayId = kDisplayId1, .hwcDisplayId = 42, .isPrimary = true});
-    const auto display2 = mFakeDisplayInjector.injectInternalDisplay(
-            [&](FakeDisplayDeviceInjector& injector) {
-                injector.setDisplayModes(kDisplay2Modes, kDisplay2Mode60->getId());
-            },
-            {.displayId = kDisplayId2, .hwcDisplayId = 41, .isPrimary = false});
-
-    mScheduler->registerDisplay(display1);
-    mScheduler->registerDisplay(display2);
+    mScheduler->registerDisplay(kDisplayId1,
+                                std::make_shared<RefreshRateSelector>(kDisplay1Modes,
+                                                                      kDisplay1Mode60->getId()));
+    mScheduler->registerDisplay(kDisplayId2,
+                                std::make_shared<RefreshRateSelector>(kDisplay2Modes,
+                                                                      kDisplay2Mode60->getId()));
 
     using DisplayModeChoice = TestableScheduler::DisplayModeChoice;
     TestableScheduler::DisplayModeChoiceMap expectedChoices;
@@ -380,13 +360,10 @@
     }
     {
         // This display does not support 120 Hz, so we should choose 60 Hz despite the touch signal.
-        const auto display3 = mFakeDisplayInjector.injectInternalDisplay(
-                [&](FakeDisplayDeviceInjector& injector) {
-                    injector.setDisplayModes(kDisplay3Modes, kDisplay3Mode60->getId());
-                },
-                {.displayId = kDisplayId3, .hwcDisplayId = 40, .isPrimary = false});
-
-        mScheduler->registerDisplay(display3);
+        mScheduler
+                ->registerDisplay(kDisplayId3,
+                                  std::make_shared<RefreshRateSelector>(kDisplay3Modes,
+                                                                        kDisplay3Mode60->getId()));
 
         const GlobalSignals globalSignals = {.touch = true};
         mScheduler->replaceTouchTimer(10);
diff --git a/services/surfaceflinger/tests/unittests/TestableScheduler.h b/services/surfaceflinger/tests/unittests/TestableScheduler.h
index 2814d38..95c9915 100644
--- a/services/surfaceflinger/tests/unittests/TestableScheduler.h
+++ b/services/surfaceflinger/tests/unittests/TestableScheduler.h
@@ -32,15 +32,13 @@
 
 class TestableScheduler : public Scheduler, private ICompositor {
 public:
-    TestableScheduler(std::shared_ptr<RefreshRateSelector> selectorPtr,
-                      ISchedulerCallback& callback)
+    TestableScheduler(RefreshRateSelectorPtr selectorPtr, ISchedulerCallback& callback)
           : TestableScheduler(std::make_unique<mock::VsyncController>(),
                               std::make_unique<mock::VSyncTracker>(), std::move(selectorPtr),
                               callback) {}
 
     TestableScheduler(std::unique_ptr<VsyncController> controller,
-                      std::unique_ptr<VSyncTracker> tracker,
-                      std::shared_ptr<RefreshRateSelector> selectorPtr,
+                      std::unique_ptr<VSyncTracker> tracker, RefreshRateSelectorPtr selectorPtr,
                       ISchedulerCallback& callback)
           : Scheduler(*this, callback, Feature::kContentDetection) {
         mVsyncSchedule.emplace(VsyncSchedule(std::move(tracker), nullptr, std::move(controller)));
@@ -68,16 +66,15 @@
     auto& mutablePrimaryHWVsyncEnabled() { return mPrimaryHWVsyncEnabled; }
     auto& mutableHWVsyncAvailable() { return mHWVsyncAvailable; }
 
-    auto& mutableLayerHistory() { return mLayerHistory; }
+    auto refreshRateSelector() { return holdRefreshRateSelector(); }
+    bool hasRefreshRateSelectors() const { return !mRefreshRateSelectors.empty(); }
 
-    auto& mutableDisplays() { return mDisplays; }
+    auto& mutableLayerHistory() { return mLayerHistory; }
 
     size_t layerHistorySize() NO_THREAD_SAFETY_ANALYSIS {
         return mLayerHistory.mActiveLayerInfos.size() + mLayerHistory.mInactiveLayerInfos.size();
     }
 
-    auto refreshRateSelector() { return holdRefreshRateSelector(); }
-
     size_t getNumActiveLayers() NO_THREAD_SAFETY_ANALYSIS {
         return mLayerHistory.mActiveLayerInfos.size();
     }
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index ff79ce0..35c037c 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -842,7 +842,8 @@
             sp<DisplayDevice> display = sp<DisplayDevice>::make(mCreationArgs);
             mFlinger.mutableDisplays().emplace_or_replace(mDisplayToken, display);
             if (mFlinger.scheduler()) {
-                mFlinger.scheduler()->registerDisplay(display);
+                mFlinger.scheduler()->registerDisplay(display->getPhysicalId(),
+                                                      display->holdRefreshRateSelector());
             }
 
             DisplayDeviceState state;